This invention generally relates to micro-electromechanical system (MEMS) devices, and more particularly, to the fabrication of self-assembling MEMS to facilitate their manufacture using current state of the art semiconductor fabrication processes.
Products using MEMS technology are widespread in the biomedical, aerospace, automotive and communications industries. Conventional MEMS require complex multilevel processing in order to produce even the simplest machines. Most entities that are interested in exploring the MEMS market have limited options for prototyping devices and little or no expertise. Often, the processes and materials required are not compatible with their current process flows.
Conventional MEMS typically utilize cantilever switches, membrane switches, and tunable capacitor structures. MEMS devices are manufactured using micro-electromechanical techniques and are used to control electrical, mechanical or optical signal flows. Such devices, however, present many problems because their structure and innate material properties require them to be manufactured in lines that are separate from conventional semiconductor processing. This is usually due to different materials and processes which are not compatible and, therefore, which cannot be integrated in standard semiconductor fabrication processes.
U.S. Pat. No. 5,994,159 to Aksyuk et al. describes a plurality of hinged plates attached to a support which upon actuation assemble into a final structure. Such a method is limited in its ability to build complex MEMS structures, since the movable parts are hinged and will not move, inherently requiring that the parts of the assembly be fabricated in-situ albeit in a different orientation. As MEMS become more complex with larger part counts, such a technique is no longer feasible.
In view of the foregoing drawbacks presently encountered in the industry, there is a need for a process that is capable of providing MEMS devices using established BEOL (Back-end of the line) materials coupled to processing that is fully integrated in order that these devices be manufactured either in conjunction with or as an add-on module to the conventional BEOL or interconnect levels.